The prior document (Korean Patent No. 10-1068862) discloses a system for managing energy in real time through a power energy collecting server, which is capable of most efficiently managing energy by monitoring, data-forming, analyzing, and supplying energy consumed in a building for each usage by synchronizing respective sensors for electricity, water supply, gas, cooling/heating, and the like.
However, the existing automatic meter reading (AMR) device, advanced metering infrastructure (AMI), or a digital watt-hour meter has a limit of collecting only information (active power, reactive power, a power factor, a frequency, and the like) on the total power energy amount consumed by a combination of all of the energy usage devices after a point, at which a corresponding power energy collecting server is installed, so that there exists a limitation in analyzing the power consumption amount or a power consumption pattern of the individual energy usage devices to provide detailed energy saving information or control the individual energy usage device through the analysis. In order to monitor or control energy of an individual home appliance using power energy, in general, a plurality of energy measuring devices or hardware for control may be separately installed in each energy usage device for collecting each power information, which has a limit to be considered as a preferable method because of a limitation of an installation place and an increase in an equipment investment.